Variation in sperm formation patterns in jumping plant-lice (Hemiptera: Psylloidea): a light microscopic study.

The patterns of sperm formation in sternorrhynchous jumping plant-lice are reviewed. To date information is available for 143 species belonging to 54 genera, 17 subfamilies and seven of the eight psylloid families (only Phacopteronidae is not represented). For the majority of the taxa (116 species, 39 genera, 10 subfamilies and the families Calophyidae, Carsidaridae and Liviidae) the data presented here is new and is based exclusively on studies using light microscopy. Five distinct patterns of chromatin reorganisation during metamorphosis of spermatids into spermatozoa are recognised, described and named here types I-V. Types I and III were previously known, types II, IV and V are described here for the first time for jumping plant-lice. The most widespread is type I which is found in every family representing the plesiomorphic condition of spermiogenesis in Psylloidea. Types III and V are autapomorphic for the Aphalarinae and Spondyliaspidinae, respectively. Type IV was found only in two genera of Euphyllurinae and may represent a synapomorphy. Type II occurs in several unrelated subfamilies and is interpreted as a homoplasy. The patterns of sperm formation are stable within most of the examined subfamilies and can be used, to a certain extent, to elucidate phylogenetic relationships within Psylloidea.